JP4510388B2 - Master cylinder for an electrohydraulic braking system with improved pedal feel simulation means and electrohydraulic braking system with such a master cylinder - Google Patents

Abstract

The master cylinder for a motor vehicle electrohydraulic brake has a cartridge (28) to simulate reaction forces on the brake pedal. The cartridge (28) has a piston (42) subjected to brake fluid master cylinder pressure on one face (44) and having a resistance spring (48) engaging the opposite face (46). The spring is a helicoidal spring with a spacer (80) between two coils to allow contact of the coils with the spacer beyond a preset brake fluid pressure.

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention mainly relates to a master cylinder for an electrohydraulic braking system comprising improved pedal feel simulation means and an electrohydraulic braking system including such a master cylinder.
[0002]
[Prior art]
The electrohydraulic braking system includes a master cylinder that simulates a mechanical response of a conventional braking circuit that the driver feels with a brake pedal during normal operation, and means for detecting the driver's operation on the brake pedal, The detecting means sends information to the computer, and the computer generates a command for sending pressurized brake oil to the brake to the hydraulic pump. When the operation is deteriorated, for example, when the pump does not react, the master cylinder supplies pressurized brake oil to the brake as in the conventional braking circuit.
[0003]
A master cylinder for a known type of electrohydraulic braking system comprises a substantially cylindrical body, in which a boring provided is divided into at least one supply chamber and a working chamber by a piston, said piston being It is mounted on the bore in an airtight sliding manner and is actuated by an actuating rod connected to the brake pedal. The piston can communicate between the two chambers during a pause, and the two chambers can be hermetically separated during braking. The supply chamber is airtightly connected to the brake oil reservoir, and the working chamber is connected to a pedal sensation simulation cartridge or pedal sensation cartridge during normal operation, and is connected to at least one brake located at the wheel position during operation deterioration. The
[0004]
The pedal sensation cartridge includes an exterior that defines a generally cylindrical chamber within which the piston slides, the piston being a pressurized brake supplied by the actuation chamber by a first surface during a braking phase during normal operation. According to the oil, according to the second surface, according to the first end of the elastic means, the second end of the elastic means is supported at the bottom of the chamber opposite the piston. The elastic means can simulate the mechanical response of a conventional braking circuit. This response corresponds to a relationship that relates the force on the pedal as a function of the pedal stroke. The characteristic curve of this relational expression has at least one first part corresponding to the absorption of the braking circuit at the start of the braking phase and then a second part corresponding to an increasing response with increasing braking level. Including.
[0005]
Thus, known types of elastic means used in pedal-like cartridges are very complex and expensive, for example, multiple coil springs with different loads at constant and variable pitches, Includes an elastic member. In addition, the assembly time is long and the number of parts required to properly simulate the conventional pedal response is high, resulting in high costs.
[0006]
The electrohydraulic braking system can control brakes and automobiles well, but cannot be considered for application to a wide range of automobiles because the simulation means of the braking circuit response is relatively complex and requires precise adjustment.
[0007]
Moreover, automobile equipment manufacturers want to standardize the components that make up the braking system as much as possible. However, since the pedal feel of each type of automobile is characteristic, at present, the pedal feel simulation means of each type of automobile must be significantly modified.
[0008]
For car drivers, it is very interesting to be able to modify the pedal feel according to the desired type of driving, but that is not possible with existing means. In particular, when a plurality of people who desire different braking comforts drive a car, the car computer stores the pedal-sensitive device adjustments for each driver who can use the car, and automatically adjusts when the driver is identified. Could be done.
[0009]
It is also possible to consider reducing the number of members constituting the simulation cartridge by using, for example, a single spring.
[0010]
It is inappropriate to use a coil spring with a regular pitch. This is because the stiffness coefficient k of these springs is constant, and the deformation force Fd is linearly related to the axial deformation x by the formula Fd = k * x, and this relation is as long as the spring is elastically deformed. This is because it is effective.
[0011]
There are also variable-pitch springs, whose deformation force is nonlinearly related to the axial deformation of the spring, the characteristics of which are close to those of conventional braking circuits. Alternatively, the simulation pedal feel cannot be adjusted according to the driver's type.
[0012]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide a master cylinder for an electrohydraulic braking system that has a simple configuration and enables a simulation pedal feeling that is very close to the response of a conventional braking circuit.
It is also an object of the present invention to provide a master cylinder for an electrohydraulic braking system that can be easily applied to various vehicle types.
[0013]
It is also an object of the present invention to provide a master cylinder for an electrohydraulic braking system in which the simulated pedal feel can be easily adjusted.
[0014]
Another object of the present invention is to provide a master cylinder for an electrohydraulic braking system that can be used in a plurality of types of automobiles.
[0015]
[Means for Solving the Problems]
These objects are achieved by a master cylinder including a pedal feel simulation cartridge with elastic means for reproducing the response of a conventional braking circuit, the elastic means comprising at least one of the first coil spring and the first coil spring. Spacer means arranged between two windings, said spacer means having two axially facing support surfaces for the two windings, the windings being supported by the spacer means Modify the stiffness of the elastic means when done.
[0016]
In other words, the elastic means includes a spring having a plurality of windings, and the springs are coupled to a spacer interposed between the plurality of windings of the spring, whereby a plurality of sets separated by a single winding spacer. A spring winding is formed. As the load on the spring increases, the windings of the spring gradually and continuously come into contact with the part of the spacer arranged between each set of windings, thus continuously increasing the rigidity of the elastic means, thus The brake pedal generates a response close to that of a conventional braking circuit.
[0017]
In fact, the stiffness of the elastic means determines the response of the pedal sensation simulation cartridge, and the stiffness of the elastic means is inversely proportional to the number of working windings of the coil spring. When a certain load is applied to the spring, the winding that moves in the axial direction with respect to the other winding is called the working winding.
[0018]
As a result, when a load is applied to the elastic means according to the present invention, the winding zone of the spring gradually contacts the spacer means, and the winding zone is next to this winding zone in the direction of loading. Continue until the winding zone or the previous winding zone is fixed. The next or previous winding zone is an “inactive” winding zone that forms a support and stops operation of the active winding zone.
[0019]
Advantageously, the cross-section of the spacer is variable along the axis of the spring, so that a modified change in the stiffness of the elastic means is obtained and a response very close to that of a conventional braking circuit is obtained.
[0020]
Moreover, the response felt by the brake pedal can be corrected by changing the relative position of the spacer means with respect to the spring, so that, for example, the change in stiffness of the elastic means can be corrected and is advantageously controlled by the computer of the braking system. Can be provided.
[0021]
The present invention mainly includes A master cylinder for an electrohydraulic braking system, A boring body with a longitudinal axis at the center, and a supply chamber and an operating chamber that are airtightly attached to the bore and are airtightly coupled to the brake oil reservoir and axially bored. Split and simulate the reaction of the braking circuit at the brake pedal and the piston controlled by the actuating rod connected to the brake pedal Pedal feel simulation The working chamber communicates with the interior of the pedal sensation simulation cartridge during normal operation, and communicates with at least one brake disposed at a wheel position when operation deteriorates, Pedal feel simulation The cartridge includes a piston capable of following the pressurized brake oil supplied from the working chamber by the first surface and the variable rigid elastic means by the second surface, wherein the elastic means comprises at least one first A coil spring and at least two windings of said coil spring line Spacer means disposed between , Product Brake oil in the moving room Pressure Over the specified value Then Said spacer means But with respect to the spacer means Winding The support The pedal feel simulation cartridge includes adjustment means for adjusting the simulation pedal feel by correcting the axial position of the spacer means relative to the coil spring. It is characterized by Ru Star cylinder providing .
[0022]
The present invention also provides a master cylinder characterized in that the spacer means is formed from a spiral forming a winding. providing .
[0023]
The present invention also provides a master cylinder characterized in that the cross-sectional dimension of the helix of the cartridge increases or decreases continuously in the helix portion along the longitudinal axis. providing .
[0024]
The present invention also provides a master cylinder characterized in that the spacer means is made of a plastic material. providing .
[0025]
The present invention also provides a master cylinder characterized in that the coil spring has a regular pitch. providing .
[0026]
The present invention also provides spacer means comprising: Pedal feel simulation A master cylinder having a second longitudinal end fixedly attached to a cartridge piston providing .
[0027]
According to the present invention, there is provided a master cylinder characterized in that the adjusting means includes a step motor that enables rotational movement of the spacer means in the longitudinal direction. providing .
[0028]
The present invention also provides a means for detecting a driver's brake operation, a computer that receives information from the detection means and generates a control command for operating at least one brake disposed at a wheel position, and a command for the computer In response, a pressure generator that sends pressurized oil to the brake, a pedal-like simulation during normal operation, a master cylinder that serves as a source of pressurized brake oil during operation deterioration, and the master cylinder during normal operation An electrohydraulic braking system, wherein the master cylinder is a master cylinder according to the present invention. providing .
[0029]
The present invention also provides a braking system in which the pressure generator is an electric pump. providing .
[0030]
The invention will be better understood from the attached drawings and the following description. In the figure, the front, rear, upper part and lower part respectively correspond to the left, right, upper and lower parts of the attached drawings.
[0031]
The members having substantially the same shape or the same function are denoted by the same reference numerals.
[0032]
DETAILED DESCRIPTION OF THE INVENTION
In FIG. 1, a known type of master cylinder with a body 2 centered on a longitudinal axis X is shown. The main body 2 has a blind hole 4 centered on the axis X and is divided into a first hydraulic circuit 6 and a second hydraulic circuit 8. Since the structures of the first and second hydraulic circuits are similar, only the first hydraulic circuit 6 will be described.
[0033]
The first circuit 6 includes a hydraulic piston 10 which is airtightly slidably attached to the boring 4 by a packing 12 having a lip attached to an annular groove 14 provided around the piston 10. . The piston 10 at its rear part accommodates a longitudinal front end 16 of an actuating rod 18 configured in a toggle joint shape, and the actuating rod is rearward in the longitudinal direction on a brake pedal (not shown) arranged in the passenger compartment of the automobile. Connected by end 20. The piston 10 divides the boring 4 into a supply chamber 22 arranged behind the piston 10 and a working chamber 24 in front of the piston 10. Supply chamber is airtight In steps Accordingly, the operation chamber is connected to the brake oil reservoir 26, connected to the pedal feel simulation cartridge 28 during normal operation, and connected to a brake disposed at the wheel position during operation deterioration.
[0034]
The piston 10 has in its central part a longitudinal passage 30 with a valve 32, which communicates the supply chamber and the working chamber during a pause and isolates the two chambers 22, 24 during the braking phase. To do.
[0035]
A return means 25 for the piston 10 is arranged in the first working chamber 24.
[0036]
Contrary to the first circuit 6, the second circuit is never hydraulically connected to the cartridge 28. In fact, during normal operation, the second working chamber 34 is isolated from the braking circuit, and during operation deterioration, the second working chamber is connected to the brake by a line 36. This line opens in a rest state and a loss of operation and connects the second working chamber 34 to the brake.
[0037]
The second piston 31 includes an annular packing 35 on the outer periphery thereof, and this packing is provided in a shoulder 33 that is provided around the boring 4 and shuts off the communication between the working chamber 24 and the inside of the cartridge 28 when the operation is deteriorated. Collaborate.
[0038]
The pedal-like simulation cartridge 28 having an axis Y substantially perpendicular to the axis X of the master cylinder body includes a substantially U-shaped exterior 38. The exterior includes an open one end 37 that is airtightly secured to the master cylinder body and a bottom 39 and defines an internal chamber 40 in which the piston 42 is mounted in an airtight slide. The piston follows the reaction of the elastic means 48 on the first surface 44 according to the pressure in the first working chamber 24 and on the second surface 46 opposite the first surface 44. Brake oil is fed from the working chamber 24 to the cartridge by a conduit 50 provided in the master cylinder body substantially perpendicular to the axis X.
[0039]
The main body of the master cylinder 2 includes a first sleeve 43 and a second sleeve 41 that are coaxial with the axis Y. The first sleeve 43 borders the conduit 50 and accommodates a part of the piston 42 in an airtight sliding manner. . The second sleeve 41 surrounding the first sleeve 43 includes means 45 for fixing the cartridge to the master cylinder body, such as a screw nut 45, for example.
[0040]
The piston 42 is of a composite type and includes a first cylindrical portion 422 that slides in an airtight manner on the first sleeve 43 by packing having a lip. The lip is disposed in a groove 424 provided on the outer periphery of the first cylindrical portion 422. The first tubular portion 422 has a first longitudinal end 426 that is blocked by a bottom 428 in front of the conduit 50 and a second end of the downward T-shaped piston 42 facing the first end 426. A longitudinal second end 430 that accommodates a portion 425. A T-shaped leg 432 is slidably attached to the first tubular portion 422. The coil spring 434 is compressed and attached between the head portion 436 of the T-shape 425 and a shoulder provided in the first cylindrical portion 422. The piston 42 also includes a U-shaped third portion 438 that is oriented from bottom to top in the figure. This portion surrounds the first sleeve 43 and the bottom 440 of the U-shape 438 accommodates the head of the second portion 425. The third part comprises a flange 442 extending radially outward at the open upper end.
[0041]
Between the bottom 428 of the first portion 422 and the legs of the T-shaped 432, an elastic block 444 made of, for example, elastomer is disposed.
[0042]
The elastic means 48 for simulating the pedal feeling includes a first coil spring 434 having a constant pitch, a variable pitch coil spring 60 that is compression-fitted between the outer bottom 39 and the flange 442, a cartridge bottom 39 and a coil. An elastomeric projection 62 sandwiched between the lower end 64 of the spring 60 in the longitudinal direction, which simulates the reaction sensation at the pedal during maximum braking at the end of the stroke of the conventional braking circuit.
[0043]
The coil springs 434 and 60 operate in their elastic deformation region when the brake is operated.
[0044]
Next, the operation of the conventional master cylinder will be briefly described.
[0045]
When acting on the brake pedal, the piston 10 moves against the spring 25 in the direction indicated by arrow A, closes the valve 32 and isolates the chambers 22, 24. The volume of the working chamber 24 decreases and the pressure in the working chamber increases and acts on the first surface 44 of the piston 42. When the pressure in the working chamber 24 exceeds a predetermined value, the piston 42 moves according to the arrow B against the spring 434 and then against the spring 60.
[0046]
Initially, the spring 434 can simulate the absorption of a conventional braking circuit. Thereafter, since the pitch of the spring 60 is variable, the relationship between the movement of the piston 42 and the pressure exerted on the first surface 44 of the piston 42 is not linear, and is close to that of a conventional braking circuit (see FIG. 2).
[0047]
At the end of the stroke corresponding to the maximum braking force, the piston 440 The protrusion 62 is crushed by. This simulates saturation in a conventional braking circuit.
[0048]
The piston of the second circuit does not move.
[0049]
When the operation is deteriorated, the pipeline 36 of the second circuit is opened, the second piston 31 is moved by the movement of the first piston 10, and the annular packing 35 is pressed against the shoulder 33, whereby the working chamber 24, the cartridge 28, Close communication between. In this case, the master cylinder operates as a conventional master cylinder.
[0050]
Although the above master cylinder is satisfactory, it has a complex configuration and cannot change the reaction simulated by the cartridge.
[0051]
There is also an electrohydraulic braking system with a single circuit master cylinder, ie it contains only one pressure piston, so that a single working chamber is connected to the pedal sensation cartridge during normal operation and fails. In this case, two or four brakes arranged at wheel positions are supplied.
[0052]
FIG. 3 shows a pedal feel simulation cartridge 32 according to the present invention. Since the master cylinder is the same as the master cylinder described above, only the cartridge 32 will be described.
[0053]
The cartridge 32 according to the present invention includes a generally U-shaped sheath 38 about the axis Y, the U-shaped top forming a first end 37 that is open in the longitudinal direction of the cartridge, which is the master. Airtightly connected to the cylinder body 2. A longitudinal second end opposite the first end 37 forms the bottom 39 of the cartridge, and is advantageously bordered by a generally annular flange 68 through which adjustment means can be passed.
[0054]
The sheath 38 defines an internal chamber 40 in which the piston 42 is mounted in an airtight slide. This airtightness is ensured by, for example, a lip packing 70 that is fixedly attached to an annular groove 72 provided in the periphery of the piston 42 so as to face the inner side surface of the chamber 40. Of course, the shape of the piston 42 is not limiting, and the use of a piston as shown in FIG. 1 does not depart from the scope of the present invention.
[0055]
The piston 42 hermetically seals the chamber 40 into an upper hydraulic chamber 74 partially defined by the first surface 44 of the piston 42 and a lower “dry” chamber 76 defined by the second surface 46 of the piston 42. Divide into Contrary to chamber 74, chamber 76 does not contain brake oil and is therefore described as “dry”.
[0056]
The sheath 38 also includes elastic means 48 attached to the lower chamber 76, which elastic means includes at least one coil spring 78 centered about the axis Y, which spring and the second face 46 of the piston 42. , Preferably compressed and attached between an outer bottom 79 comprising an annular surface 68 defining a hole 60.
[0057]
The spring 78 according to the illustrated embodiment is a regular pitch coil spring, which means that the spring 78 includes first windings Sn spaced apart by a fixed dimension, the illustrated example. Then, the spring includes windings S1, S2, S3, S4, S5, S6, and S7 separated by a fixed length of intervals I1, I2, I3, I4, and I5, respectively.
[0058]
However, it is also conceivable to provide variable-pitch coil springs, cylindrical or conical coil springs with a circular or rectangular winding in cross section.
[0059]
The spring 78 operates within the range of its elastic deformation when the brake is operated.
[0060]
The elastic means 48 also has a spacer means 80 (FIG. 3 ′) which is preferably helical around the axis Y and includes a second winding Zn. The illustrated example includes Z1, Z2, Z3, Z4, and Z5. The spacer means 80 can cooperate with the first spring 78 so that the second windings Z1, Z2, Z3, Z4, Z5 are arranged at intervals I1, I2, I3, I4, I5, respectively. .
[0061]
The winding Zn of the spacer means 80 has a sufficient lateral dimension so that the winding Sn of the coil spring 78 can be supported.
[0062]
If the spring 78 is conical, the spacer means 80 is advantageously conical, approximately equal to the conical shape of the spring 78.
[0063]
The spacer means 80 includes an upper free end (not shown) and a lower end 83, and the lower end is fixed to a plug that closes the hole 60 after the spacer means is installed, or a simulation pedal feel adjusting means 82. Fixed to.
[0064]
Of course, the spring 78 can include any number of turns Sn, and the spacer means can include a number of turns different from the number of spacings In.
[0065]
In the illustrated embodiment, the helix forming the spacer means 80 comprises a winding with an axial dimension e along the axis Y, this dimension decreasing continuously along the direction of the arrow C. The cross sections of the windings Z1, Z2, Z3, Z4, and Z5 shown in FIG. 3 are axial dimensions e1, e2, e3, e4, and e5, respectively, e2 is smaller than e1, and e3 is e. 2 E4 is smaller than e3 and e5 is smaller than e4.
[0066]
Of course, the spacer means are arranged in the opposite direction between the windings of the spring 78 in the sheath 38 so that the axial dimension along the axis Y of the spiral forming the spacer means 80 increases continuously in the direction of arrow C. You may make it do.
[0067]
Of course, the spacer means 80 consisting of spirals with axial dimensions that vary monotonically along the axis Y also does not depart from the scope of the present invention.
[0068]
The cross section of the helix is advantageously rectangular, but a helix with a circular or oval cross section, for example, does not depart from the scope of the invention.
[0069]
Further, not all the intervals In need to include the winding Zn of the spacer means 80.
[0070]
Here, n is a positive integer of 1 or more.
[0071]
The spacer means 80 is advantageously made of a plastic material which is easily elastically deformed in the operating range of the elastic means 48, but for example the windings of the spring 78 while elastically approaching the winding Zn of the spacer means. The metallic material or any other material that forms the rigid spacer between Sn does not depart from the scope of the present invention.
[0072]
The illustrated embodiment also includes a simulation pedal spacing adjustment means 82 that allows the stress characteristics and stroke first part to be particularly modified. This corrects the alignment of the windings Z1, Z2, Z3, Z4, Z5 in the intervals I1, I2, I3, I4, I5, and the axial position of the spacer means 80 relative to the spring 78, in particular the intervals I1, I2, The thickness of the spacer portion arranged between the windings of the spring 78 is corrected by correcting the state of the windings Z1, Z2, Z3, Z4, and Z5 in I3 and I4. Thus, the adjusting means 82 can move the winding Zn at the spacing In toward the spacing In + 1 or In-1 according to the desired pedal spacing correction, for example, the winding Z5 moves from the spacing I5 towards the spacing I4. Move and so on.
[0073]
The adjusting means 82 includes a stepping motor that can tighten, for example, the spacer means 80 in the spring 78 in the direction of the arrow V or loosen in the direction of the arrow D, and the windings Z1, Z2, Z3, Z4, Z5 are screws The intervals I1, I2, I3, I4, and I5 form screw holes.
[0074]
Next, the operation of the pedal feel simulation cartridge according to the present invention will be described. Therefore, consideration is given to the movement of the windings S1, S2, S3, S4, S5, and S6 when a load is applied to the elastic means, particularly the coil spring. When it is described that the winding Sn and the winding Zn are in contact with each other, it naturally means that the winding zone Sn and the winding zone Zn are in contact with each other gradually and gradually.
[0075]
When acting on the brake pedal, the piston 10 moves along the arrow A against the spring 25, closing the valve 32 and isolating the chambers 22,24. The volume of the working chamber 24 decreases, the pressure in the working chamber increases and acts on the first surface 44 of the piston 42 in the same way. When the pressure in the working chamber 24 exceeds a predetermined value, the piston 42 moves according to the arrow B against the spring 78.
[0076]
FIG. 4 shows a first example showing the pedal stress characteristic C1 as a function of pedal stroke, which is roughly comparable to the response of the piston 42 shown as a function of piston 42 movement.
[0077]
The characteristic C1 includes a first portion P1 corresponding to the start of movement of the piston 42 which acts to compress the spring 78, and the intervals I1, I2, I3, I4, I5 simultaneously reduce their respective lengths d. The dimension d of the intervals I1, I2, I3, I4, I5 is larger than the dimension e1, in which case the winding zones S1, S2 are not yet in contact with the winding zone Z1.
[0078]
When the dimension d is equal to the dimension e1, the winding zones S1, S2 come into contact with the winding zone Z1, and the winding zone Z1 Is no longer accessible to the winding zone S1, and the winding zone S2 is in a so-called inactive state, so that the rigidity of the elastic means 48 is increased and the gradient of the characteristic C1 is increased.
[0079]
The spring 78 continues to be elastically deformed and supports the windings S2 and S3 successively and gradually with respect to the winding Z1 of the spacer means 80, in which case the winding S3 is deactivated and the rigidity of the elastic means is increased again. As a result, the gradient of the characteristic C1 increases.
[0080]
Since the gradient changes are made continuously, the pedal feel is very close to that felt by a conventional braking circuit.
[0081]
As the driver continues to increase the force applied to the brake pedal, the piston 42 continues to compress the spring 78, bringing the windings of the spring 78 and the spacer means windings into contact again, and continuously increasing the characteristic gradient. To increase.
[0082]
When all of the windings of the spring 78 separated by the spacer means 80 are in contact with the windings of the spacer means 80, the stiffness gradient of characteristic C1 will result in the spring winding not being separated by the winding of the spacer means and hence the acting force. As the increases, the more accessible spring windings become constant until they are touched simultaneously, and the springs are no longer elastically incompressible. This does not correspond to the normal operation of the master cylinder.
[0083]
Therefore, the elastic means 48 corresponds to a variable pitch spring that can be corrected.
[0084]
Elastic means having springs with variable pitch and spacer means with constant or otherwise axially dimensioned windings do not depart from the scope of the present invention.
[0085]
4, 5 and 6 show the characteristics C1, C2 and C3 with respect to the maximum dimension in the axial direction of the winding Zn of the spacer means arranged between the windings Sn of the increasing spring 78. FIG. This change is obtained by loosening the spacer means 80 with a spring 78 or by moving the spacer in the direction of the arrow E by means of an adjusting device. This extends the braking start zone corresponding to the absorption of the conventional circuit.
[0086]
Of course, the axis Y of the cartridge can be oriented in any direction other than perpendicular to the axis X of the master cylinder body.
[0087]
FIG. 7 shows an electrohydraulic braking system according to the present invention. This system comprises a master cylinder MC according to the invention in which an actuating rod 18 connected to a brake pedal 86 is actuated, a longitudinal movement detection means 88 of the actuating rod 18 such as, for example, a stroke sensor, and said sensing means. A computer which receives 88 information and generates a control command to operate the brake 92 90 And a pressure generator 94 such as an electric pump for sending pressurized oil to the brake 92 in response to a command from the computer 90, and an electromagnetic valve 96 for blocking communication between the master cylinder and the brake during normal operation. The electromagnetic valve is opened at rest and when operation deteriorates.
[0088]
When the driver activates the brake pedal 86, the detecting means 88 sends information to the computer 90, and the computer generates a command in the pump 94 to send pressurized oil to the brake 92. The simulation response corresponding to a conventional braking circuit is communicated to the driver by a brake pedal that provides the possibility of adjusting the brake level of the driver.
[0089]
Of course, a master cylinder with a single hydraulic circuit consisting of a supply chamber and a pressure chamber, in which the pressure chamber is connected to a pedal-like simulation cartridge with elastic means according to the present invention, is outside the scope of the present invention. do not do.
[0090]
As described above, master cylinders having pedal sense simulation means having an effective and simple structure are configured, and advantageously, these master cylinders are easily and speedily attached to various types of automobiles and adapted to the technology. And / or can be adapted to the desires of car drivers.
[0091]
The invention applies in particular to the automotive industry.
[0092]
The present invention is particularly applicable to the brake industry for automobiles, and in particular to the brake industry for private cars.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a master cylinder for an electrohydraulic braking system according to the prior art.
FIG. 2 is a curve showing pedal feel characteristics of a conventional hydraulic circuit.
FIG. 3 is a longitudinal sectional view showing details of a master cylinder according to the present invention.
FIG. 3 ′ is a perspective view of the member of FIG.
FIG. 4 is a graph showing a pedal-like characteristic curve obtained with the electrohydraulic braking system according to the present invention for one adjustment.
FIG. 5 is a graph showing pedal-like characteristic curves obtained with the electrohydraulic braking system according to the present invention for other adjustments.
FIG. 6 is a graph showing a pedal-like characteristic curve obtained with the electrohydraulic braking system according to the present invention for further adjustment.
FIG. 7 is a schematic view of an electrohydraulic braking system according to the present invention.
[Explanation of symbols]
2 body
4 boring
6 First hydraulic circuit
8 Second hydraulic circuit
10, 42 piston
12 Lip packing means
14 annular groove
18 Actuating rod
22 Supply chamber
24 Working chamber
28 Pedal feel simulation cartridge
44 First side
46 Second side
48 Elastic means
78 First coil spring
80 Spacer means
82 Adjustment means
88 detection means
90 calculator
92 Brake
94 Pressure generator
96 Solenoid valve
B direction
R Brake oil reservoir
Sn first winding
Zn Second winding

Claims (9)

A master cylinder for an electrohydraulic braking system, which has a body (2) centered on a longitudinal axis (X) with a boring (4) open, and an airtight slide mounted on the boring. A piston (10) controlled axially by an actuating rod connected to a brake pedal and divided axially into a supply chamber (22) and an actuating chamber (24) which are hermetically coupled to the oil reservoir (R); A pedal feel simulation cartridge for simulating the response of the braking circuit in the brake pedal, and the operation chamber (24) communicates with the inside of the pedal feel simulation cartridge (28) during normal operation, and the wheel position during operation deterioration. communication with at least one brake is positioned on the pedal feel simulation cartridge ( 8), the first surface (44), in accordance with pressurized brake oil supplied from the working chamber (24), the second surface (46), a piston can follow the variable stiffness of the elastic means (48) (42) wherein the resilient means (48), and at least one first coil spring (78), spacer means arranged between at least two windings of said coil spring (78) (Sn) (80) and a, the pressure of the brake oil within the work Doshitsu (24) exceeds a predetermined value, said spacer means (80), it is possible to support the winding relative to said spacer means The pedal feel simulation cartridge (28) adjusts the simulation pedal feel by correcting the axial position of the spacer means (80) relative to the coil spring (78). A master cylinder comprising adjusting means (82) .   2. A master cylinder according to claim 1, characterized in that the spacer means (80) is formed from a helix forming a winding (Zn).   The master cylinder according to claim 2, wherein the cross-sectional dimension of the helix increases or decreases continuously in the helix portion along the longitudinal axis.   4. A master cylinder according to claim 1, wherein the spacer means (80) is made of a plastic material.   5. A master cylinder according to claim 1, wherein the coil spring (78) has a regular pitch. A spacer means having a longitudinal second end (83) fixedly attached to a piston (42) of a pedal sensation simulation cartridge (28). The master cylinder described in the item. The master cylinder according to any one of claims 1 to 6 , characterized in that the adjusting means comprises a stepping motor that allows rotational movement of the spacer means (80) in the longitudinal direction. Detection means (88) for driver's brake operation and a computer (90) for receiving control information from the detection means (88) and generating a control command for operating at least one brake (92) arranged at the wheel position And a pressure generator (94) for sending pressurized oil to the brake (92) in response to a command from the computer (90), enabling simulation of pedal feeling during normal operation, and pressure brake oil source during operation deterioration The master cylinder which plays the role of and the solenoid valve (96) which interrupts | blocks communication between the said master cylinder and a brake at the time of normal operation | movement, The said master cylinder is any one of Claim 1 to 7 An electro-hydraulic braking system characterized by being a master cylinder. 9. Braking system according to claim 8 , characterized in that the pressure generator (94) is an electric pump.

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